The Lefortovo Tunnel runs underground for 3 kilometres on the outskirts of Moscow. The deep tunnel has three lanes which are equipped with traffic sensors every 60 metres. These have provided a rich vein of traffic data for Boris Livshits and pals at Moscow Technical University who have been a-mining and a-crunchin it.
B Livshits says the data shows there are four distinct phases of traffic flow: free flow, light synchronised traffic, heavy synchronised traffic and jam. They’ve even found that that traffic undergoes a phase change when the lane occupancy rises above 32 per cent. When that happens, the average speed of the traffic drops suddenly by at least 15 km/h.
But they missed a trick here. Traffic planners want to be able to prevent jams by spotting the telltale signs that they are about to form and then slowing everything down or reducing lane occupancy in way that prevents the jam forming.
But B Livshits and friends ain’t got anything to say about what causes jams to form. Perhaps they ain’t got the right kinda data. Maybe studying the video below, taken in the tunnel, might help ’em better understand the cause of jams.